PD Node1 PD + PD() + PD() + add() + add() + add() + add() + operator const string() + dump() Node2 std::ostringstream Node2->Node1 -ATLAS_THREAD_SAFE Node3 std::basic_ostringstream < char > Node3->Node2 Node4 std::basic_ostream < Char > Node4->Node3 Node5 std::basic_ios< Char > Node5->Node4 Node6 std::ios_base Node6->Node5 Node7 std::map< string, vector < string > > Node7->Node1 -m_dat Node8 string Node8->Node7 +keys Node9 vector< string > Node9->Node7 +elements